1. Field of the Invention
The present invention relates to a steam turbine plant, for example, including a collector configured to collect water from steam in a high pressure turbine or stream exhausted from the high pressure turbine.
2. Background Art
FIG. 22 is a schematic diagram illustrating a first example of a conventional steam turbine plant using solar heat. A steam turbine cycle in the plant of FIG. 22 will be described.
A heat medium 118 is transferred by a heat medium pump 116 to a solar energy collector 119 collecting solar heat. The heat medium 118 is, for example, oil. The heat medium 118 is heated by radiant heat of solar rays 117 in the solar energy collector 119. Subsequently, the heat medium 118 is transferred to a heater 110 which is a heat exchanger to heat water or steam corresponding to a heating object. The heat medium 118 decreases in the temperature in the heater 110, and returns to the upstream of the heat medium pump 116. In this manner, the heat medium 118 circulates.
The heat medium 118 stored in a heat storage tank is circulated while bypassing the solar energy collector 119 at nighttime when solar rays 117 cannot be received or daytime when the solar rays 117 are weak, but the equipment and the flow for this configuration are not shown herein.
The steam turbine cycle of FIG. 22 is configured as a single-stage reheat cycle which is a reheat turbine 113 including a high pressure turbine 101, an intermediate pressure turbine 102, and a low pressure turbine 103.
The heater 110 includes a boiler 108 which changes feed-water 111 into steam 112 and a reheater 109 which heats steam dedicated for the reheat turbine 113. The feed-water 111 is transferred by the pump 105 to the boiler 108 which is a part of the heater 110 and is heated in the boiler 108, so that it changes into the high pressure turbine inlet steam 112.
The high pressure turbine inlet steam 112 flows into the high pressure turbine 101 and expands inside the high pressure turbine 101, so that the pressure and the temperature all decrease. The high pressure turbine 101 is driven by the high pressure turbine inlet steam 112. In the steam turbine cycle using solar heat, the temperature of the high pressure turbine inlet steam 112 is low in many cases compared to the steam turbine cycle using exhaust heat of a combustion gas of a fuel. For this reason, the high pressure turbine exhaust 114 is not dry steam only composed of a gas, but humid steam composed of a mixture of a gas and a liquid. That is, the dryness of the humid steam is less than 1 in many cases.
In FIG. 22, the outlet (exhaust port) located at the most downstream of the high pressure turbine 101 is denoted by the reference character X. The high pressure turbine exhaust 114 flows into the reheater 109 which is a part of the heater 110 to be heated therein, and flows into the intermediate pressure turbine 102.
The intermediate pressure turbine inlet steam 106 expands inside the intermediate pressure turbine 102, decreases in both the pressure and the temperature, and flows into the low pressure turbine 103. The low pressure turbine 103 of FIG. 22 is a double flow type in which the intermediate pressure turbine exhaust 123 flows from the center of the low pressure turbine 103 left and right, and flows out of two outlets. The steam flowing into the low pressure turbine 103 expands inside the low pressure turbine 103, decreases in both the pressure and the temperature, and flows out as humid steam. Due to this steam, the intermediate pressure turbine 102 and the low pressure turbine 103 are driven as in the high pressure turbine 101.
The steam flowing out of the low pressure turbine 103, the low pressure turbine exhaust 115 flows into a condenser 104. The condenser 104 cools the low pressure turbine exhaust 115 using cooling water, and returns the cooled exhaust to the feed-water 111. The feed-water 111 is returned to the upstream of the pump 105. In this manner, the feed-water 111 circulates while changing into the steam 112. Furthermore, seawater or stream water may be used as the cooling water, and the cooling water increasing in the temperature in the condenser 104 may be circulated by being cooled in a cooling tower using atmosphere.
The rotary shafts of the high pressure turbine 101, the intermediate pressure turbine 102, and the low pressure turbine 103 are connected to a generator 107. Its rotary shaft is rotated with the rotation of the high pressure turbine 101, the intermediate pressure turbine 102, and the low pressure turbine 103 due to the expanding steam. The generator 107 generates power in accordance with the rotation of the rotary shaft.
In FIG. 22, the extraction ports provided at the halfway stages of the high pressure turbine 101, the intermediate pressure turbine 102, and the low pressure turbine 103 are denoted by the reference character E, and extraction steam 120 is extracted from one or more of the extraction ports E. In FIG. 22, a recycling cycle (a reheat recycling cycle) is configured such that the feed-water 111 is heated by the extraction steam 120 serving as a heat source in the feed-water heater 121 between the condenser 104 and the boiler 108. The cycle of FIG. 22 may not be the recycling cycle, but the efficiency of the cycle improves in the case of the recycling cycle.
Furthermore, the extraction steam 120 is cooled in the feed-water heater 121 to change into water, and merges with the feed-water 111 by a drain water pump 122.
FIG. 23 is a schematic diagram illustrating a second example of the conventional steam turbine plant using solar heat. In FIG. 23, the flow of the heat medium 118 is not shown, and this will be omitted even in the respective drawings to be described later.
In many cases, the inlet steam of the reheat cycle using solar heat is close to a humid region with, for example, a pressure of 110 ata and a temperature of 380° C. in the enthalpy-entropy diagrammatic view, and the high pressure turbine exhaust 114 becomes humid steam. The humid steam inside the high pressure turbine 101 causes humidity loss, and deteriorates the internal efficiency of the turbine. Further, since water droplets collide with the surface of the turbine vane of the high pressure turbine 101, erosion is caused.
Therefore, the high pressure turbine 101 of FIG. 23 includes a collector which collects water from the steam inside the high pressure turbine 101. Then, the steam turbine plant of FIG. 23 includes a collected matter path P which makes collected matter 201 collected by the collector flow into the condenser 104. In FIG. 23, the collection place where water is collected from the high pressure turbine 101 is denoted by the reference character Y. The collected matter 201 flows from the collection place Y into the condenser 104 through the collected matter path P. In some cases, the collected matter 201 may contain humid steam or dry steam collected with water as well as the collected water.
Hereinafter, first to third configuration examples of the collector will be described.
FIG. 24 is a schematic diagram illustrating a first example of the collector.
As shown in FIG. 24, the high pressure turbine 101 includes plural stages of rotor vanes 301 and plural stages of stator vanes 302. Then, in FIG. 24, a drain catcher 304 is provided at an inner wall surface 303 on the outer peripheral side of the steam passage. The drain catcher 304 is the first configuration example of the collector.
The drain catcher 304 is connected to the condenser 104 through the pipe (the collected matter path P). Since the internal pressure of the condenser 104 is lower than that of the high pressure turbine 101, moisture present in the inner wall surface 303 is suctioned outward as the collected matter 201, and flows into the condenser 104. Accordingly, the amount of the moisture contained in the steam inside the high pressure turbine 101 decreases.
FIG. 25 is a schematic diagram illustrating a second example of the collector.
There is shown a groove attached rotor vane 311 configured to more actively remove moisture than the first configuration example. In FIG. 25, a groove 305 is provided at a surface of a rotor vane 301 (311) of a turbine stage to which humid steam flows, so that water droplets 306 contained in the humid steam are captured. The captured water droplets 306 move toward the outer periphery of the rotor vane 301 along the groove 305 due to the centrifugal force exerted on the surface of the rotating rotor vane 301. Then, the water droplets 306 fly toward the drain catcher 304 provided on the inner wall surface 303.
The drain catcher 304 is connected to the condenser 104 through the pipe (the collected matter path P). Since the internal pressure of the condenser 104 is lower than that of the high pressure turbine 101, the moisture present inside the drain catcher 304 is suctioned outward as the collected matter 201, and flows into the condenser 104. Accordingly, the amount of the moisture contained in the steam inside the high pressure turbine 101 decreases. The drain catcher 304 and the groove attached rotor vane 311 are the second configuration example of the collector.
The collector shown in FIG. 24 or 25 may be provided in the intermediate pressure turbine 102 or the low pressure turbine 103 so long as it is a turbine stage to which humid steam flows. However, when the groove attached rotor vane 311 is applied to the final-stage rotor vane 301 of the low pressure turbine 103, no effect is obtained since there is no rotor vane 301 at the downstream of the final-stage rotor vane. For this reason, the groove attached rotor vane 311 is applied to the rotor vane 301 which is located upstream of the final-stage rotor vane 301 of the low pressure turbine 103.
FIGS. 26 to 28 are schematic diagrams illustrating a third example of the collector.
There is shown a slit attached stator vane 312 configured to more actively remove moisture than the first configuration example. FIG. 26 is a diagram when the slit attached stator vane 312 is seen from the cross-section including the rotary shaft of the turbine, and FIG. 27 is a diagram when the slit attached stator vane 312 is seen from the cross-section perpendicular to the rotary shaft of the turbine. Further, FIG. 28 is a diagram illustrating the cross-section perpendicular to the radial direction with respect to one slit attached stator vane 312.
In FIGS. 26 to 28, a slit 307 is provided on the surface of the stator vane 302 (312) at the turbine stage to which humid steam flows. In addition, a hollow space 308 is provided inside the stator vane 312, and the stator vane 312 is configured as a hollow vane. The surface of the stator vane 312 and the hollow space 308 are connected to each other through the slit 307. The slit attached stator vane 312 is the third configuration example of the collector.
The hollow space 308 is connected to the condenser 104 through the slit 307 and the pipe (the collected matter path P). Since the internal pressure of the condenser 104 is lower than that of the vicinity of the slit 307, the water droplets 306 or the water membrane flowing to the surface of the slit attached stator vane 312 are suctioned outward as the collected matter 201, and flows into the condenser 104. Accordingly, the amount of the moisture contained in the high pressure turbine 101 decreases.
Further, the water droplets 306 or the water membrane flowing to the surface of the stator vane 302 are separated from the surface of the stator vane 302 in the form of water droplets and scatter to the downstream, so that the water droplets collide with the downstream rotor vane 301. However, according to the slit attached stator vane 312, the amount of the water droplets 306 especially decreases in this manner.
The collector shown in FIGS. 26 to 28 may be provided in the intermediate pressure turbine 102 or the low pressure turbine 103 so long as it is a turbine stage to which humid steam flows.
Furthermore, since the low pressure turbine exhaust 115 decreases in the pressure until it changes into humid steam regardless of the property and the state of the inlet steam, in the steam turbine cycle using solar heat, the high pressure turbine exhaust 114 and the low pressure turbine exhaust 115 are humid steam.
FIG. 29 is a diagram illustrating an example of an expansion line of the conventional steam turbine plant shown in FIG. 22 or 23. The vertical axis of FIG. 29 indicates the enthalpy, and the horizontal axis indicates the entropy.
In FIG. 29, there are shown a high pressure turbine expansion line 401, a reheat turbine expansion line 402, and a saturation line 403. Since the intermediate pressure turbine 102 and the low pressure turbine 103 are reheat turbines continuous to each other, the expansion line for such a turbine becomes one expansion line.
In FIG. 29, there are shown a high pressure turbine inlet point 404, a high pressure turbine outlet point 405, a reheat turbine inlet point (an intermediate pressure turbine inlet point) 406, and a reheat turbine outlet point (a low pressure turbine outlet point) 407.
In FIG. 29, the high pressure turbine exhaust 114 is heated in the reheater 109 up to a temperature equal to that of the high pressure turbine inlet steam 112. Further, in FIG. 29, there is a change exceeding the saturation line 403 when the steam changes from the high pressure turbine inlet point 404 to the high pressure turbine outlet point 405 or from the reheat turbine inlet point 406 to the reheat turbine outlet point 407. Therefore, in the high pressure turbine inlet point 404 or the reheat turbine inlet point 406, the steam is dry steam. In the high pressure turbine outlet point 405 or the reheat turbine outlet point 407, the steam is humid steam.
FIG. 29 relates to the high pressure turbine expansion line 401, where there are shown a dry region R1 in which the steam is dry steam and a humid region R3 in which the steam is humid steam. FIG. 29 relates to the reheat turbine expansion line 402, where there are shown a dry region R2 in which the steam is dry steam and a humid region R4 in which the steam is humid steam.
Furthermore, JP-A 2006-242083 (KOKAI) discloses an example of a steam turbine plant that is equipped with a moisture separator.
Further, JP-A H11-22410 (KOKAI), JP-A 2004-124751 (KOKAI), and JP-A H11-159302 (KOKAI) disclose examples of a steam turbine plant that is equipped with a collector for collecting moisture.